Rule.



I" M. BRWIN.

RULE.

APPLICATION FILED JULY 25, 1913.

Patented sept.8,19141 m, SY N lverted into the units of another scale.

FRANK M. ERWIN, 0F LOUISVILLE, KENTUCKY.

RULE.

Specification of Letters Patent.

Patented Sept. 8, 1914.

Application led July 25, 1913. Serial No. 781.186.

To all 'wlw/n. it may concern:

Be it known that I, FRANK M. ERWIN, a citizen of the United States, residing at Louisville, in the county of Jefferson and State of Kentucky, have invented new and useful Improvements in Rules, of which the following is a specification.

This invention relates to a rule, the primary object being to provide a device of this character which is in the form of an elongated flat body having straight edges and whose outer surface includes beveled side portions and an intermediate groove in which a. slide constructed of transparent material is mounted for longitudinal movement, the said slide having lateral wings overlying the beveled surfaces of the body and provided with a common cross hair or fine line which is disposed at right angles to the longitudinal axis of the body. Upon one beveled face of the rule body a number of longitudinally extending scales, such as those intended for the use of an architect, are inscribed, one of the scales being disposed at the outer edge thereof. Upon the other beveled surface, similarly disposed en gineers scales are provided. By the use of the slide described above, the inwardly disposed scales upon either surface of the body may be used, owing to the fact that any points thereon may be transferred to the edge of the rule by adjusting the slide so that its cross hair will cover the desired point.

A further object of the invention is to provide conversion scales preferably at one end of the rule upon the opposite beveled surfaces thereof, and which include longitudinally separated scales. By adjusting the slide with reference to these scales, linear distance upon one scale may be con- The usefulness of this means of convenient and rapid conversion to an architect or engi* neer should be readily apparent.

A still further object is to provide a rule body and a slide associated therewith, together with simple and readily operable means for automatically securing the slide in its different longitudinally adjusted positions in a comparatively rigid manner.

The invention consists in the features of construction, combination, and arrangement of parts, hereinafter fully described and claimed, reference being had to the accompanying drawing, in which:

Figure l is a top plan view of the device. showing the slide in position for converting measurement upon one of the conversion scales into units of another conversion scale, the position of the slide for transferring a point of measurement upon an interior scale to the outer edges of the rule body being indicated in dotted lines; Fig. 2 is a transverse sectional View taken on line 3--3 of Fig. l; Fig. 3 is a longitudinal sectional view taken on line 3 3 of Fig. l' and, Fig. 4 is-a detail perspective View of the slide.

In the drawing. the numeral l designates the elongated body of the rule which has straight, parallel. longitudinal edges 2 and 3. Adjacent to each of the straight edges, the outer surface of the body is beveled as at 4 and its intervening plane portion 5 is provided with a longitudinally extending groove G which is dove-tailed so as to snugly receive the similarly shaped body 7 of a 1ongitudinally movable slide. The slide body is provided in its inner face with a recess 8 in which the terminals of a longitudinally bowed leaf spring 9 are engaged, the medial portion of the spring being adapted for frictional engagement within a longitudinal groove 10 provided inedially within the inner face of the dove-tailed groove 6 of the rule body. This spring is normally under tension so as to force the beveled side faces 11 of the body portion of the slide into snug engagement with the correspondingbeveled faces 12 of the body groove (i, it being understood that the body portion of the slide is fitted loosely within the groove of the rule body so as to be free for slight vertical movement. Transversely alining, laterally projecting wings 13 are provided upon the slide and have their inwardly inclined, ta-

pered portions ll disposed immediately above the correspondingly inclined surfaces 4 of the rule body so as to be slightly spaced therefrom when the slide is in its normally rigid position. The slide as a Whole is constructed of Celluloid or other suitable transparent material and is provided upon its inner surfaces with a cross hair 14a or suitablj,r formed fine straight line which is disposed at right angles to the longitudinalaxis of the rule body and connects the sharp points l5 of the companion wings 13 of the slide. rlhese wing points project nearly to the outer side edges of the rule body, which latter are inclined at a greater angle to the base surface 1G of the rule body than the angle of inclination of either inclined surface e.

shovvnin thedrawing, one of a number of architects scales is inscribed upon the edge 3 of the rule body Whereas the other scales of this group extend longitudinally upon the adjacent beveled surface d interiorly with respect to the iirst-named scale.

These graduations may be inscribed upon the rule body in any suitable manner, depending chiefly upon the material from which the saine is constructed. lf the body is formed of metal, these surfaces may be graduated by etching or otherwise cutting into the same, whereas, the graduations may be drawn in ink lines upon the body when it is constructed of Wood or other like material.

. Similarly disposed engineers scales are inscribed upon the opposite beveled face Llof the rule body and the outermost scales are provided upon the edge surface Q. Adjacent to one end of the rule body, a conversion scale l is inscribed upon one of the beveled surfaces i and includes longitudinally separated portions which coact with another conversion scale B provided upon the opposite beveled surface.

ln using the device for measuring linear distance upon any desired surface, the body of the rule is positioned s0 that one of its side edges will bear against the surface to be measured. Then the body portion T of the slide is forced inwardly by properly manipulating the same with the fingers against action ofits spring 9, so that the beveled side edges ll of the slide body Will be freed from their snug frictional engagement with J' the side faces l2 of the slot G provided in the rule body. rlhe slide may now be freely moved along the body of the rule and it is brought into such a position that the point l5 of one of its Wings 13 will coincide with one of the terminals of the line to be measured. By the aid of the cross hair 14a, the corresponding point upon any one of the interiorly dispo-ed scales upon either beveled surface of thiA rule body may be determined. Then, the slide is moi ed so that the point of one of its Wings will coincide with the opposite terminal of the line to be measured and another point upon the desired scale is located in the same manner. By computation, the length upon the desired scale may be dnt rmined. ln laying off linear distances upon any surface, the scale may be employed in transferring measurements from any one of the interiorly disposed scales to one of the side edges of the rule idioten body as should be readily understood by those skilled in the art to Which this nvention appertains.

In the drawing, the English units scale in the architects group of scales is shown exteriorly disposed, whereas the English units scale of the engineerls group is interiorly disposed. This Varrangement is preferably adopted in connection with rules which are intended primarily for use by architects, but it is to be understood that the arrangement should be reversed upon rules to be used by engineers. The device may thus be manufactured in distinct types which are designed to meet the particular requirements of the diderent classes of professional men Who would use such a rule.

ll'hen it is desired to convert measurement of one scale into terms of another scale, the slide is released and moved into registration with the desired conversion scale, as shown particularly in Fig. l of the drawing. When the slide is disposed so that its cross hair will register with a given point upon one of the scales, the corresponding point upon the opposed scale may be determined, and in this manner the distance between points upon one scale may be converted into measurement upon another scale. The different conversion scales may be printed upon the rule body in distinct colors, if found practicable, in order that the diderent scales may be readily distinguishable.

From the foregoing description, taken in connection with 'the accompanying dravvings, it should be apparent that ll have provided a simply constructed and readily operable rule, which may be used conveniently and with great accuracy by engineers, architects, or draftsmen for a number of purposes. l desire to have it understood, however, that minor changes falling Within the scope of the appended claims may be resorted to in practice if found necessary.

Having thus described my invention, what l claim is:

liti

l. A measuring instrument of the class described comprising a body having parallel longitudinal edges and plane upper surfaces adjacent said edges provided with longitudinal scales thereon, the said body being provided medially with a longitudinally eX tending dove-tailed groove, a slide including a dove-tailed body loosely engaged Within the said groove for longitudinal ,sliding movement and lateral Wings projecting from said dove-tailed body and overlapping the graduated surfaces, the said slide bein constructed of transparent material A an having a cross hair adapted to register with the graduations of the scale, and yieldable means for normally forcing the beveled side edges of the dove-tailed body into' snug engagement with the corresponding Walls of the said dove-tailed groove.

2. A measuring instrument of theI class described comprising a body having parallel longitudinal edges and plane upper surfaces adjacent said edges provided With longitudinal scales thereon, the said body being provided medially with a longitudinally extending dove-tailed groove, a slidel including a dove-tailed body loosely engaged within the said groove for longitudinal sliding movement and lateral Wings projecting from said body-portion and overlying the graduated surfaces, the said slide being constructed of transparent material and having across hair adapted to register Witlr the graduations of the scales, the bottom of the said dove-tailed groove being provided with a second medially disposed and longitudinally extending groove, the body portion of the slide being provided with a medial recess in its inner face -registering with the last-named body groove, and a spring engaged Within the said recess of the siide for frictional contact Within the last-named body groove.

3. A measuring instrument of the class de- `scribed comprising a body having parallel longitudinal edges and plane upper surfaces adjacent said edges provided with longitending dove-tailed groove, a slide including a dove-tailed body loosely engaged Within the said groove for longitudinal sliding movement and lateral Wings projecting.

from said body portion and overlying the graduated surfaces, the said slide being constructed of transparent material and having a cross hair adapted to register with the graduations of the scales, the bottom of the said dove-tailed groove being provided with a second medially disposed `and longitudinally extending groove, the body portion of the slide being provided with a medial recess in its inner face registering With the last-named 'body groove, and a longitudinally bowed leaf-spring having its terminals engaged Within the slide recess and having its medial portion in contact Within the last-named body groove.

In testimony whereof I ax my signature in presence of two Witnesses.

FRANK M. ERWIN.

Witnesses:

O. L. VANDAMENT, D. C. BETTIsoN. 

